Pipe end machining device with axial autofeed

ABSTRACT

A device for preparing the end of a pipe includes a non-rotatable mandrel one end of which is attachable to the pipe. A motor rotates a sleeve around the mandrel and the sleeve retains an arm perpendicular to the mandrel for cutting the pipe. A cam surface on the rotating sleeve moves a cam follower. Movement of the cam follower is converted to rotational movement for turning a feed nut threaded on the mandrel. The rate at which the sleeve is advanced by the feed nut is controlled by limiting the movement of the cam follower.

The applicants claims priority from their previously filed provisionalapplication assigned Ser. No. 61/235,768 and filed Aug. 21, 2009. Thepresent invention relates to a device for machining the end of a pipe toprovide a bevel suitable for welding and in particular to an autodrivefor machining a compound bevel angle without requiring thereconfiguration of the machine.

BACKGROUND OF THE INVENTION

Extended piping requires that shorter lengths of pipe be welded togetherend to end to form a longer section and prior to joining two lengthstogether, the mated ends must be machined to receive a weld. Where thewall of the pipe is relatively thin, the distal end of the pipe may bemachined into a simple bevel. Where the wall of the pipe is thicker, acompound bevel is required. A typical compound bevel has one portionangled at ten degrees and a second portion angled at thirty-sevendegrees.

Machines that bevel the distal end of a length of pipe are elongate witha first end structured to engage the inner surface of a length of pipeand retain the machine rigid with respect to the pipe. The second end ofthe machine includes a rotating member with a cutting end. Some machinescan be configured to automatically cut a bevel at a fixed angle, forexample, cut at ten degrees. Such machines must be reconfigured if theyare subsequently required to cut a second portion of a bevel atthirty-seven degrees. Other machines move the tool radially at a fixedrate and provide a manually operable feed screw for moving the toolaxially. The rate at which the axial feed screw is operated determinesthe angle of the bevel being cut. The operator can therefore rotate thefeed screw at a first rate, for example, one revolution of the screw foreach revolution of the cutting tool to form a first bevel angle ofthirty-seven degrees and then change the feed rate, for example, tothree rotations of the feed screw for each rotation of the cutting toolto cut a bevel at ten degrees. However, the operation of such a machinerequires constant attention from the operator. It may take forty-fiveminutes or longer for a machine to cut a bevel at the distal end of alength of pipe, and if the operator fails to properly adjust the feedscrew after each revolution or sequence of revolutions of the cuttingtool, the bevel will not be properly formed. It would be desirable,therefore, to provide a device for machining the end of a length of pipethat is capable of forming a compound bevel without requiring thereconfiguration of the machine or requiring that an operator manuallyrotate a feed screw.

SUMMARY OF THE INVENTION

Briefly, the present invention is a device for preparing the end of alength of pipe that includes an elongate non-rotatable shaft having aclamp at one end that includes a plurality of moveable shoes forapplying force to the inner surface of a length of pipe to therebyretain the shaft to the pipe. A housing at the second end of the shaftretains a sleeve rotatable around the shaft and an arm extendingradially from the sleeve. A motor rotates the sleeve and the arm, andthe sleeve is axially moveable along the shaft.

A cutting tool suitable for cutting the pipe is radially moveable alongthe arm and a drive radially moves the tool as the sleeve rotates aboutthe shaft thereby providing a linear relationship between rotation ofthe sleeve and radial movement of the tool.

A portion of the shaft has a threading and a feed screw rotates on thethreading for axially advancing the sleeve. The rotating sleeve has anannular cam surface thereon that moves a cam follower mounted on thehousing. Movement of the cam follower is converted into rotationalmovement that rotates a gearing connected to the feed screw foradvancing the sleeve along the shaft in response to movement of the camfollower.

The device further includes a control for controlling the outer limitsof movement of the cam follower thereby controlling the rate at whichthe gearing is rotated thereby controlling the rate of axial movement ofthe feed screw and axial movement of the cutting tool. Accordingly,adjustment of the control changes the limits of movement of the camfollower and changes the axial speed of the cutting tool, therebychanging the angle of the bevel being cut. By merely changing thecontrol, the device will change the angle of the bevel being cut withoutrequiring an operator to reconfigure the machine.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the invention will be had after a reading ofthe following detailed description taken in conjunction with thedrawings wherein:

FIG. 1 is an isometric view of a device in accordance with the presentinvention;

FIG. 1A is another isometric view of the device taken from the oppositeside, with a portion of the housing broken away;

FIG. 2 is a cross-sectional view of the device shown in FIG. 1 attachedto a length of pipe;

FIG. 3 is an exploded view of the device show in FIG. 1, showing themajor components thereof;

FIG. 4 is an exploded view of the mounting assembly for retaining thedevice shown in FIGS. 1 and 2 to the length of pipe;

FIG. 5 is an exploded view of the facing arm of the device shown FIGS. 1and 2 that engages and cuts the distal end of a length of pipe;

FIG. 6 is an exploded view of the autofeed assembly that providesrotational power for axially moving the facing arm shown in FIG. 5;

FIG. 7 is an exploded view of the feed that axially drives the facingarm and cutting tool shown in FIG. 5;

FIG. 8 is a cross-sectional view of the mandrel shown in FIGS. 2 and 3;

FIG. 9 is a side elevational view of the chuck shown in FIG. 4;

FIG. 10 is a cross-sectional view of the chuck shown in FIG. 9;

FIG. 11 is a rear end view of the chuck shown in FIG. 9;

FIG. 12 is a side elevational view of one of the chuck legs shown inFIG. 4;

FIG. 13 is an elevational view of the outer end of the chuck leg shownin FIG. 12;

FIG. 14 is a cross-sectional view of the main shaft shown in FIG. 2;

FIG. 15 is an end view of a locking nut and cam shown in FIG. 2;

FIG. 16 is a cross-sectional view of the locking nut and cam shown inFIG. 15 taken through line 16-16 thereof;

FIG. 17 is a side elevational view of the cam follower shaft shown inFIG. 6;

FIG. 18 is a side elevational view of the cam follower shown in FIG. 6;

FIG. 19 is an end view of the cam follower shown in FIG. 18;

FIG. 20 is a side elevational view of the stop, the stop shaft, and thestop adjusting arm assembled together and visible in FIG. 2;

FIG. 21 is an end view of the stop, the stop shaft, and the stopadjusting arm as shown in FIG. 20;

FIG. 22 is a side elevational view of the intermediary gears and shaftshown in FIGS. 2 and 29;

FIG. 23 is a rear end view of the feed nut drive gear shown in FIG. 7;

FIG. 24 is a cross-sectional view of the feed nut drive gear shown inFIG. 23 taken through line 24-24 thereof;

FIG. 25 is a front end view of the feed nut drive gear shown in FIG. 23;

FIG. 26 is a cross-sectional view of the feed nut adapter shown in FIG.7;

FIG. 27 is a cross-sectional view of the feed nut drive gear assembledto the feed nut adapter shown in FIG. 26 and the feed nut shown in FIG.23 with two shifter pins inserted into the assembled parts;

FIG. 28 is a side elevational view of a shifter pin shown in FIGS. 7 and27;

FIG. 29 is an isometric view of the cam follower, the stop, the scalefor adjusting the stop, and the intermediary gears driven by the camfollower shaft, and

FIG. 30 shows a collection of different sizes of shoes attachable to thedevice shown in FIGS. 1 and 2 to accommodate a range of sizes of pipe.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

Referring to FIGS. 1, 2, and 3, a device 10 for machining the distal endof a length of pipe 12 has an elongate central shaft or mandrel 14 atone end of which is a mounting assembly 16 for retaining the mandrel 14axially aligned with the longitudinal axis of the pipe 12 and at theopposite end of which are housing portions 18 and 19 that assembletogether and are non-rotatable with respect to the mandrel 14. Thedevice also includes a motor 20, a rotating arm 22, and radiallymoveable along the arm 22 a tool holder 24 for retaining a cutting tool26. When in operation, the arm 22 rotates around the mandrel 14 and thecutting tool 26 is moved by the tool holder 20 and the arm 22 to cut acompound bevel 27 at the outer end of the length of pipe 12.

To cut a compound bevel 27, the device 10 includes an adjustableautofeed 28 that can adjustably fix the axial rate at which the housing18, 19 is axially advanced with respect to the mandrel 14 therebyaxially moving the arm 22 and the tool 26. For the purposes of thisdiscussion, the mounting portion 16 will be described as being at therearward end of the device 10 and the housing 18, 19 positioned at theforward end thereof. In similar fashion, the mandrel 14 has a rearwardend retaining the mounting assembly 16 and a forward end retaining thehousing 18, and all longitudinally oriented parts likewise have forwardand rearward ends.

Referring to FIGS. 2, 4, and 8, the mandrel 14 is a hollow cylinder, theouter surface of which has a rearward cylindrical portion 29. Forward ofthe cylindrical portion 29 are centrally located splines 30, and forwardof the splines 30 is a smaller diameter threaded portion 31. A radialshoulder 32 defines the intersection between the splines 30 and theforward threaded portion 31. The central opening 33 of the mandrel 14 iscylindrical. An annular shoulder 34 is spaced a short distance from theforward end of the mandrel 14 and female threads 35 extend a shortdistance into the rearward end thereof.

Rotatably mounted within the mandrel 14 is an elongate threaded draw bar36 having a hex nut 37 non-rotatably mounted to the outer end thereofsuch that an operator can rotate the hex nut 37 and the draw bar 36using a conventional hand wrench, not shown. An annular flange 38 at therearward end of the nut 37, axially retains the draw bar 36 with respectto the inner surface of the mandrel 14. The rearward surface of theflange 38 abuts the annular shoulder 34 in the inner surface of themandrel 14 and the forward surface of the flange 38 abuts an annularretainer 39 to thereby retain the draw bar 36 against axial movementwith respect to the mandrel 14.

Referring to FIGS. 2, 4, 8, 9, 10, 11, 12, 13, and 30, the mountingassembly 16 at the rear end of the mandrel 14 includes a chuck body 40that is symmetrical about its longitudinal axis and at the forward endof which is a cylindrical threaded portion 41 that is threadedlyreceived in the female threads 35 at the rearward end of the mandrel 14.The rearward end of the chuck body 40 has a plurality of grooves 42therein equally spaced around the circumference thereof. Each of thegrooves 42 has a ramped bottom surface 44 and opposing side surfaces 46,48, one of which 48 has an associated undercut 50 therein. An axial hole51 extends through the length of the chuck body 40 that rotatablyreceives the draw bar 36.

Slideably fitted within each of the grooves 42 is a wedge-shaped chuckleg 54 having a lower surface 56 adapted to slide along the bottomsurface 44 of one of the grooves 42. One of the opposing walls 52 ofeach of the chuck legs 54 is indented forming a ridge 58 along one sideof the lower surface 56 which are slideably received within the undercut50 of the chuck body 40. Each chuck leg 54 also has a generally planarupper surface 60 having at least two tapped holes 62 therein forreceiving retaining screws 64 for retaining one or more sets ofremovable shoes 66. The rearward end 67 of each chuck leg 54 also has atransverse groove 69 therein thereby forming a ridge 68 along the rearface of the chuck leg 54 that is perpendicular to the upper surface 60.

The shoes 66 that are attachable to the outer surface 60 of each leg 54are preferably available in a plurality of lengths. As depicted in FIG.30, the shoes may be available in four distinct lengths with shoe 66Abeing the longest and shoe 66D being the shortest. By assemblingdifferent combinations of shoe lengths to each leg 54, the length of thelegs 54 can be adjusted to retain the mandrel 14 in any diameter of pipe12.

On the distal end of the draw bar 36 is an annular end plate 72 having aforward surface 74 with a plurality of radially directed grooves 76therein for receiving the rearward ends 67 of each chuck leg 54 and athreaded central opening 77 that threadedly receives the distal end ofthe draw bar 36. Retained in mounting holes, not shown, adjacent to eachof the grooves 76 are retaining screws, one of which 78 is shown. Eachscrew 78 has a head that engages the ridge 68 of one of the chuck legs54, thereby slideably retaining the end of the chuck leg 54 to the endplate 72. Accordingly, rotation of the hex nut 37 at the forward end ofthe draw bar 36 will rotate the draw bar 36 and cause axial movement ofthe end plate 72. Axial movement of the end plate 72 toward the hex nut37 will move all of the chuck legs 54 upwardly along the ramp surfaces44 and force the removable shoes 66 to move radially outward until theyengage the inner surface of the central opening of the pipe 12 therebylocking and retaining the mandrel 14 coaxial with the pipe 12. Rotationof the hex nut 34 in the opposite direction will withdraw the shoes andrelease the mandrel 14 from the pipe 12.

Referring to FIGS. 2 and 7, surrounding the central portion 30 of themandrel 14 is an annular coupling 80 having female splines 82 forslideably engaging the splines 30 of the mandrel 14. A plurality ofscrews 83 extend through holes, unnumbered, in the coupling 80 and intoa retaining flange that forms part of the housing 18 to retain thehousing 18 against rotation with respect to the mandrel 14 and allow thehousing 18 to move axially with respect to the mandrel 14.

Referring to FIGS. 2 and 14, rotatably mounted on bearings 86, 88 aroundthe cylindrical portion 29 of the mandrel 14 immediately rearward of thesplines 30 is a main shaft 90. The main shaft 90 is generally tubular inshape having a cylindrical inner opening 85 through with the mandrel 14extends such that the main shaft 90 forms a sleeve rotatable around themandrel 14. The forward end of the main shaft 90 has male threads 87,and rearward of the male threads 87 is a centrally located cylindricalsection 89. At the rearward end of the main shaft 90 is a radial flange92. A worm gear 94 is fitted around the central cylindrical section 89and the worm gear 94 is driven by a worm shaft 96 mounted on a shaftfrom the motor 20. The worm gear 94 is retained with respect to the mainshaft 90 by a key, not visible, in a key slot. Another set of bearings98, 100 rotatably maintain the main shaft 90 with respect to the housing18.

Referring to FIGS. 1, 2, 3, and 5, the rotating arm 22 includes amounting plate 102 retained by a plurality of bolts, not visible, to therearward surface of the flange 92 of the main shaft 90 for rotationtherewith. On opposite sides of the rearward surface of the mountingplate 102 are stiffener plates 104, 106 for rigidly retaining themounting plate 102. At the radially outward end of the mounting plate102 and stiffeners 104, 106 is an end plate 108. At the opposite end ofthe plate 102 is a feed screw block 110 having a transverse hole 111therein through which an elongate threaded feed screw 112 extends.

The stiffener plates 104, 106 are oriented parallel to one another alongthe mounting plate 102 and form a channel along which a rectangularshaped male slide 114 is slideable. The slide 114 has a transversethreaded hole 116 therein for threadedly receiving the outer end of thefeed screw 112. An enlarged diameter portion 122 of the feed screw 112forms a thrust shoulder for applying force against a surface of the feedscrew block 110 when the slide 114 it is moved radially outward. Thedistal end of the feed screw 112 has a star wheel 124 non-rotatablyretained thereto such that rotation of the star wheel 124 rotates thefeed screw 112 and causes radial movement of the slide 114. Mounted onthe slide 114 is the tool holder 24 and cutting tool 26.

As best shown in FIGS. 2, 3, and 5, mounted around the circumference ofhousing member 19 and adjacent the mounting plate 102 is an annular tripretainer 126. Positioned at equally spaced locations around thecircumference of the trip retainer 126 are a plurality of moveable trips128. Each trip 128 consists of an elongate arm 130 with a handle at oneend thereof and a centrally located transverse hole 121. Each trip 128is mounted in a U-shaped retainer 132 on a pin 123 that extends throughthe centrally located transverse hole 121 of the moveable trip andthrough aligned holes in each of the parallel sides of the U-shaped tripretainer 132. Using the handles of the various trips 128, an operatorcan position the various trips 128 into an engagement position, in whichthe trip is extended, or a non-engaging position, in which the trip isnot extended, for engaging or not engaging the points of the star wheel124 as the mounting plate 102 rotates around the mandrel 14.Accordingly, by setting or not setting the desired number of trips 128,an operator can determine the rate at which the star wheel 124 isrotated with respect to a single rotation of the mounting plate 104 andthe tool 26 about the mandrel 14, and thereby controlling the speed ofradial movement of the tool 26 with respect to the rotation of themounting plate 102.

Referring to FIGS. 1A, 2, 15, and 16, a locking nut 134 has femalethreads 125 extending into the rearward end thereof that threadedlyreceive the threads 87 of the main shaft 90 and has a forward surfacethat abuts against the bearing 98, thereby retaining the bearings 98,100 with respect to the main shaft 90. The forward end 127 of the outersurface of the locking nut 134 is frustoconical and the locking nut 134is locked to the threads 87 of the main shaft 90 by an annular lockingmember 136 having an inner surface complementary to the frustoconicalsurface 127 of the lock nut 134 to ensure that the bearing lock nut andmain shaft 90 rotate together. As best shown in FIG. 15, the rearwardend of the outer surface 138 of the threaded locking nut 134 forms a camagainst which moves a follower as is further described below. The cam138 includes a gradual ramp portion 133 along which the radius isgradually lengthened and rapid fall section 135 extending between themaximum radius and minimum radius of the gradual ramp portion 133.

Referring to FIGS. 1A, 2, 6, and 17 through 19, a fundamental element ofthe present invention is the provision of the adjustable autofeed 28 formoving the housing 18 along the mandrel 14 at a rate that can be changedwithout reconfiguring the machine to thereby form a compound bevel 27.The heart of the adjustable autofeed 28 lies in a cam follower 140mounted on a shaft 142. The shaft 142 has a threaded forward end 137.Rearward of the threaded forward end 137 is a first cylindrical portion139, and rearward of the first cylindrical portion 139 is a second,larger diameter cylindrical portion 141. Along the rearward half of thesecond cylindrical portion 141 is a key slot 143. Rearward of the keyslot 143 in cylindrical portion 141 is a large diameter cylindricalportion 145 having somewhat smaller diameter side portions 147, 149. Atthe rearward end of the cam shaft 142 is an annular groove for receivinga snap ring, unnumbered. The camshaft 142 extends parallel to themandrel 14 with the forward end retained by a bearing 144 in the housing18. The cam follower 140 has a tubular body with a generally cylindricalouter surface. The forward portion 151 of the outer surface is anuninterrupted cylinder so as to receive bearing 153 that rotatablyretains the cam follower 140 in a portion of the housing 18. Therearward portion of the cam follower 140 has a pair of spaced apartparallel ears 150, 152 with aligned transverse holes 157 therein andfitted between the ears 150, 152 and rotatable on a shaft 155 extendingthrough the holes 157 in the ears 150, 152 is a rotatable roller 154positioned to engage the outer surface of the cam 138. The cam follower140 further has a third ear 156 positioned approximately diametricallyopposite the first and second ears 150, 152. The third ear 156 has athreaded hole 158 therein for receiving a pin 160.

The cam follower 140 is fitted around the large diameter portion 145near the rearward end of the cam shaft 142, and between the enlargeddiameter portion 145 and the body of the cam follower 140 is a one-wayclutch 166. Forward of the one-way clutch 166, and mounted on the secondcylindrical portion 141 of the cam shaft 142 is a gear 168 retained by akey, not visible, in the key slot 143 for rotation with the cam shaft142. Forward of the gear 168 is a second one-way clutch 170 configuredas a backstop. The forward end of the cam shaft 142 extends through ahole, not visible, in a portion 183 of the housing and is non-rotatablyretained thereto by a collar 159 on the threaded end 137 thereof. Seals169, 163 retain lubricants and retaining rings 165, 167 retain the partsaround the cam shaft 142. The pin 160 in ear 156 receives one end of acoil spring 161, the opposite end of which connects to a pin 137 on aninner surface of the housing 18, not shown, to urge the cam follower 140to rotate the roller 154 against the surface of the cam 138. A thirdbearing 146 rotatably retains the rearward end of the cam shaft 142 withrespect to the cam follower 140. Accordingly, movement of the camfollower 140 and roller 154 against the outer surface of the cam 138causes angular rotation of the cam follower 140 on the shaft 142. Thefirst one-way clutch 166 applies an incremental angular rotation to theshaft 142 in one direction with each rotation of the cam 138 andreversal of the cam shaft 142 is prevented by the second one-way clutch170.

Referring to FIGS. 1, 2, 6, 20, 21, and 29, an important feature of theautodrive 28 is the provision of an adjustable stop 172 that limitsmovement of the cam follower 140. The adjustable stop 172 is mounted ona pivot arm 174 that is rotatable on a shaft 176 oriented coaxial withthe rearward end of the cam shaft 142. The stop 172 is adapted to abutthe third ear 156 of the cam follower 140 and thereby limit the returnof the roller 154 to contact the smallest radius portion of the cam 138.The shaft 176 extends through a housing and plate 181 and is rotated bya controlling arm 178 attached by a pin 173 to the shaft 176. A bushing171 around the shaft 176 facilitates its rotation. At the outer end ofthe controlling arm 178 is a marker 180 that is moveable along a scale182. The scale 182 is affixed to the outer surface of the end plate 181that fits against a portion of housing 183 enclosing the autofeed 28. Anend cap 217 encloses the controlling arm 178. The marker 180 and thescale 182 are visible by an operator and the controlling arm 178 islocked into a desired orientation, as shown by the marker 180 and scale182, by a locking knob 184. The locking knob 184 threadedly receives theend of a threaded stud 173 that extends slideably through a longitudinalhole 171 in the upper end of the controlling arm 178. The lower end ofthe longitudinal hole 171 opens into a rectangular opening 177 thatextends transversely through the controlling arm 178. Loosely fittedinto the rectangular opening 177 is an elongate locking plate 175 towhich the second end of the threaded stud 173 is attached. One end ofthe locking plate 175 extends into an arcuate slot 179 in the end plate181 that mates against housing portion 183. Turning the locking knob 184in one direction draws the locking plate 175 against a surface formingarcuate slot 179 in the end plate 181 thereby locking the stop 172 in adesired position. By adjusting the controlling arm 178 an operator cancontrol the range of movement of the cam follower 140 and therebycontrol the relationship between the rate of rotation of the camfollower shaft 142 with respect to the rotational rate of the main shaft90.

As best shown in FIGS. 2, 6, and 22, extending parallel to the mandrel14 and the cam follower shaft 142 is yet another shaft 186. Rotatablymounted on shaft 186 on bearings 185, 187 is an intermediary gearassembly 188. The intermediary gear assembly 188 includes a second gear190 that engages the cam shaft gear 168 and a third gear 192 that islocked for rotation with the second gear 190.

Referring to FIGS. 2, 7, and 22 through 28, the teeth of the third gear192 engage the teeth 193 of a feed nut drive gear 194. The feed nutdrive gear 194 has a large diameter central opening into which is fitteda tubular feed nut adapter 196. The feed nut adapter 196 is in turnretained by bolts 197 to a threaded feed nut 198 having internal threads199 that engage the threaded forward end 31 of the mandrel 14. Theassembled parts are rotatably retained with respect to the housing 18 bya bearing 201.

The forward half of the inner opening of the feed nut drive gear 194includes an annular rippled or serrated surface 200. The surface 200 hasequally spaced apart crests 203 shaped as blunted teeth of a gear, andbetween each pair of crests 203, is a shallow, arcuate valley 205. Thefeed nut adapter 196 has a plurality of radial holes 202 therein thatare aligned radially inward of the serrated surface 200 of the drivegear 194. Slideably fitted into each of the holes 202 is a detent ball204. Extending parallel to the axis of the feed nut adapter 196 so as tointercept each of the radial holes 202 are transverse holes 206 each ofwhich slideably receives an elongate shifter pin 208. Centrally locatedalong the length of each of the shifter pins 208 is an annular groove210 having angled side surfaces 211, and at the forward end of eachshifter pin 208 is a threading 212. Each of the shifter pins 208 extendsthrough corresponding aligned holes 213 in the feed nut 198 with thethreaded ends 212 received in complementary threaded holes, unnumbered,in an end plate 216 having a plurality of radially extending handles218. The end plate 216 and the shifter pins 208 are therefore axiallymoveable with respect to the mandrel 14, the feed nut drive gear 194 andthe feed nut adapter 196. FIG. 2 depicts the end plate 216 compressedagainst the forward surface of the feed nut 198. When the end plate 26is in this position, the shifter pins 208 are moved to their rearwardposition. In FIG. 27, shifter pin 208B is depicted as being in therearward position in which the annular groove 210 around thecircumference of each of the shifter pins 208 is aligned under itsassociated detent ball 204 allowing the ball the sink deep within itsassociated radial hole 202 and not forced into the serrated surface 200of the drive gear 194. The drive gear 194 is thereby allowed to freelyrotate around the mandrel 14. On the other hand, when an operatormanually pulls the end plate 116 away from the forward surface of thefeed screw 198, the annular grooves 210 of the shifter pins 208 aremoved away from the associated detent balls 204 as is shifter pin 208Ain FIG. 7. The balls 204 are then forced up the angled surfaces 211 ofthe shifter pins 208 so that they engage the serrated surface 200 of thedrive gear 194 and are forced into a valley 205 between two crests 203thereby drivingly connecting the drive gear 194 to the feed nut 198.When the drive gear 194 is drivingly connected to the feed nut 198,rotational movement of the cam follower shaft 142 is applied through thevarious gears 168, 190, 192, 194 to rotate the feed nut 198 with respectto the mandrel 14 thereby causing axial feed of the housing 18 withrespect to the mandrel 14. The autofeed 28 is therefore engaged when theend plate 216 is pulled away from the housing 18 and disengaged when theend plate 216 is compressed against the forward surface of the housing18. With the autodrive 28 in the disengaged orientation, that is withthe end plate 216 compressed against the housing, as shown in FIG. 2, anoperator can manually rotate the handles 218 of the end plate 216 toprovide a manual axial feed along the mandrel 14.

The angular movement of the cam follower 140 causes rotation of the camshaft 142 and the feed nut 198. The stop 172 limits the angular rotationundertaken by the cam follower 140 with each rotation of the cam 138 andtherefore, changing the position of the stop 172 changes the distancethe main shaft 90 and tool 26 are advanced with each rotation of the arm22. The scale 182 has markings 220 thereon indicative of the axial speedat which the main shaft 90 and tool 26 will be advanced. By looseningthe locking knob 184, the operator can move the marker 180 to a positionon the scale 182 indicative of a desired axial feed rate.

It should be apparent that the angle of a cut made by the tool 26 isdetermined by the combination of the rate of radial movement of theslide 114 along the arms 22 and the rate of axial movement of the mainshaft 90 along the mandrel 14. The radial movement of the slide iscaused by rotation of the star wheel 124, which is incrementally rotatedeach time the star wheel 124 engages a trip 128 that is in theengagement position. If two trips 128 are set in the engagementposition, the slide 114 and tool 26 will move at twice the radial raterelative to the axial movement of the main shaft 90 as when only onetrip 128 is set. One scale 184 is provided that has a marking that setsforth the angle to be cut by the tool 26 for various positions of thecontrolling arm 178 and marker 180 where one trip 128 is set in theengagement position. However, a second scale 184 is needed for settingthe angle of the cut where two trips 128 are set, and a third scale 184is needed for setting the angle of the cut when three trips 128 are set.As shown in FIG. 6, the housing 183 may receive two or more scales 184with each scale 184 showing angles to be cut for a different number oftrips 128 set.

To operate the device of the present invention an operator will selectthe desired combination of removable shoes 66 to fit the size pipe to bemachined and attach them by bolts to the outer ends of each of theslides 114. The retaining end of the mandrel 14 is then extended intothe length of pipe 12 and the hex head 37 rotated with a wrench untilthe device 10 is firmly retained with respect to the pipe 12.Thereafter, the desired number of trips 128 are set to fix the desiredradial rate of movement of the cutting tool 26. The locking nut 184 isloosened allowing movement of the controlling arm 178 and marker 180with respect to the scale 182 to set the desired feed rate after whichthe locking knob 184 is tightened. The motor 20 is then energizedcausing rotation of the mounting plate 102 around the mandrel 14. Usingthe handles 218 of the end plate 216 the operator can withdraw the endplate 216 to engage the autodrive 30 and cause the tool 26 to cut thedesired bevel 27 at the end of the pipe 12.

While the present invention has been described with respect to a singleembodiment, it will be appreciated that many modifications andvariations may be made without departing from the spirit and scope ofthe invention. It is therefore the intent of the appended claims tocover all such modifications and variations which fall within the spiritand scope of the invention.

What is claimed:
 1. A device for preparing an end of a length of pipe,said device comprising an elongate mandrel, a sleeve rotatably mountedon said mandrel, a radially extending arm on said sleeve, a cutting toolon said arm for machining said end of length of pipe as said armrotates, a motor for rotating said sleeve and said arm, said sleeveaxially moveable along said mandrel, a threading on said mandrel, a feednut engaging said threading for axially advancing said sleeve along saidmandrel, a cam on said sleeve, a cam follower engaging said cam, saidcam follower rotatable about a shaft, a one-way clutch between said camfollower and said shaft wherein rotational movement of said cam followeris conveyed to said shaft in only one direction, and said shaftdrivingly connected to said feed nut wherein said sleeve and saidcutting tool are axially advanced along said mandrel with each rotationof said sleeve.
 2. The device of claim 1 and further comprising a clampat one end of said mandrel said clamp having a plurality of radiallymoveable feet for engaging an inner surface of said pipe.
 3. The deviceof claim 2 and further comprising removable shoes attachable to saidradially moveable legs, said moveable shoes available in a plurality ofdifferent lengths, and said shoes longitudinally stackable wherein aplurality of sizes of said shoes can be combined for engaging said clampto a number of sizes of pipe diameters.
 4. The device of claim 1 andfurther comprising said cutting tool radially moveable along said arm,an axially rotatable feed shaft along said arm, and a drive for rotatingsaid feed shaft in response to rotation of said sleeve about said shaft.5. The device of claim 4 and further comprising a threading on said feedshaft, a non-rotatable follower nut and said feed shaft, and saidfollower nut attached to said cutting tool, wherein said cutting tool isradially moved in response to rotation of said arm about said shaft. 6.The device of claim 1 and further comprising an adjustable stop forlimiting an angle of rotation of said cam follower about said shaftwherein a repositioning of said stop will change a rate at which saidfeed nut advances said sleeve and said cutting tool.
 7. The device ofclaim 6 and further comprising a marker moveable with said stop, and ascale having markings thereon indicative of corresponding axial feedrates wherein the positioning of said marker at a chosen feed rate onsaid scale will result in said sleeve and said cutting tool beingadvanced at said chosen rate.
 8. The device of claim 1 and furthercomprising a second one-way clutch on said shaft, said second one-wayclutch configured as a backstop to prevent rotation of said shaftopposite to said rotation imposed by said cam follower.
 9. A device forpreparing an end of a length of pipe, said device comprising an elongatemandrel, a sleeve rotatably mounted on said mandrel, a radiallyextending arm on said sleeve, a cutting tool on said arm for machiningsaid end of length of pipe as said arm rotates, a motor for rotatingsaid sleeve and said arm, said sleeve axially moveable along saidmandrel, a threading on said mandrel, a feed nut engaging said threadingfor axially advancing said sleeve along said mandrel, a cam on saidsleeve, a cam follower engaging said cam, said cam follower rotatableabout a shaft, a one-way clutch between said cam follower and said shaftwherein rotational movement of said cam follower is conveyed to saidshaft in only one direction, and said shaft drivingly connected to saidfeed nut wherein said sleeve and said cutting tool are axially advancedalong said mandrel with each rotation of said sleeve; a drive geararound said feed nut, said drive gear having a serrated inner surface,said serrated inner surface having a plurality of equally spaced apartcrests and a valley between each pair of crests, said feed nut having atleast one radial hole extending into an outer surface thereof, said feednut further having an axially directed hole extending along an axis,wherein said axis of said axially directed hole intercepts an axis ofsaid at least one radial hole, a ball in said at least one radial hole,a shifter pin in said axially directed hole, said shifter pin having agroove transverse to a length thereof wherein said ball may fall intosaid groove when said groove is aligned with said radial hole, and saidball is forced into one of said valleys of said serrated surface whensaid groove is not in alignment with said radial hole, and said shifterpin axially moveable between a first position wherein said groove isaligned with said radial hole and a second position wherein said grooveis not aligned with said radial hole.
 10. A clutch for transmittingrotational force between an inner shaft and a surrounding sleevecomprising a serrated inner surface on said sleeve, said serratedsurface having a plurality of equally spaced apart crests and a valleybetween each pair of crests, said shaft having at least one radial holeextending into an outer surface thereof, said shaft further having anaxially directed hole extending along an axis, wherein said axis of saidaxially directed hole intercepts an axis of said at least one radialhole, a ball in said at least one radial hole, a shifter pin in saidaxially directed hole, said shifter pin having a groove transverse to alength thereof wherein said ball may fall into said groove when saidgroove is aligned with said radial hole, and said ball is forced into avalley of said serrated surface when said groove is not in alignmentwith said radial hole, and said shifter pin axially moveable between afirst position wherein said groove is aligned with said radial hole anda second position wherein said groove is not aligned with said radialhole; wherein said shaft is tubular having an annular wall and an axialcentral opening and said axially directed hole extends through a portionof said wall.
 11. The clutch of claim 10 wherein a second shaft extendsthrough said axial central opening, and said second shaft has malethreads thereon, and said shaft is a feed nut having female threads insaid central opening that engage said male threads wherein said clutchengages or disengages rotational power between said feed nut and saidsleeve.
 12. The clutch of claim 10 and further comprising a handle foraxially moving said shifter pin.